1. Technical Field of the Invention
The present invention relates generally to a method of and apparatus of filling an ink cartridge, which supplies ink to a print head of an ink jet type recording apparatus for ejecting ink droplets in accordance with a print signal, with ink, which ink cartridge is detachably mounted on a carriage of the recording apparatus.
2. Related Art
A print head of an ink jet type recording apparatus connects to an ink cartridge through an ink supply passage, so that ink is supplied from the ink cartridge to the print head. Generally, with the ink cartridge mounted on the carriage of the recording apparatus, a porous member impregnating with ink is accommodated within a housing of the ink cartridge having an air communication hole for the sake of preventing ink level from varying due to the reciprocating movement of the carriage, and the ink is supplied therefrom to the print head through an ink supply port formed on the housing.
When ink is filled in the ink cartridge thus designed, it is required that ink is filled sufficiently at least in the vicinity of the ink supply port. Otherwise, air which enters the housing through the air communication hole during the printing operation of the recording apparatus may reach the ink supply port, which may cause a problem that the air at the ink supply port would block the smooth flow of ink and certain amount of ink is remained within the housing. In addition, air may enter the print head and cover nozzles which may cause the undesirable white dot phenomena in which no ink droplet is ejected through the nozzle as the ink flow is blocked by the air. Those problems would deteriorate the print quality.
On the other hand, the ink cartridge with ink completely depleted has been conventionally replaced with a new ink cartridge and the old ink cartridge has been disposed. However, it is preferable to reuse the depleted ink cartridge for the purpose of preserving resources. Unexamined Japanese Patent Application No. 9-39262, for example, discloses an ink refilling technique in which ink is press-filling through an air communication hole formed in an ink cartridge. However, the air communication hole is generally designed to have a large fluid resistance in an effort to suppress evaporation of ink housed within the ink cartridge. For example, the air communication hole constructed to open to ambient air via a capillary action. Therefore, it is required to take relatively long time to fill or refill ink in the ink cartridge through the air communication hole. In addition, after the ink filling or refilling operation ink which is remained in the air communication hole maybe dried out and solidified to close the hole, thereby to stop the air intake through the air communication hole and to block ink supply through the ink supply port to the print head. This is another problem.
Furthermore, according to the conventional ink refilling technique as disclosed in JPA No. 9-39262, since ink is filled through the air communication hole which positions opposite to the ink supply port, ink filling condition in the vicinity of the ink supply port, which influences the ink supply performance of the ink cartridge, may not be high enough, and the ink supply to the print head would become unstable. Moreover, because the pores of the porous member housed in the depleted ink cartridge hold air instead of ink as ink has been exhausted through the ink supply port, it is difficult to fill ink entirely within the ink cartridge.